Elevator control



May 2l, l929- E. B. THuR'sToN 1,714,285

ELEVATOR CONTROL (immuun.

May 2l, 1929. E, B 'rl-n JRs-{QN- 1,714,285

ELEVATOR CONTROL Filed July 31, 1926 4 Sheets-Sheet 2 25% @QAM Q. (QM

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ELEVATOR CONTRL Filed July 31, 1926 4 Sheets-Sheet 3 E :L E

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May 2l, 1929. E. B. 'rHURsToN 41,714,285

ELEVATOR CONTROL Filed July 31, 1926 4 Sheets-Sheet 4 Ernest-,B Thurston.

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Patented May 21, 1929.

UNITED STATESl vPmxna'r OFFICE.

ERNEST B. THUBSTON, OE TOLEDO, OHIO, ASSIGNOR TO TEE HA'UGHTON ELEVATOB & MACHQINE COMIANY, F TOLEDO, OHIO, A CORPORATION OF OHIO. A

ELEvATon coNTnoL.

This invention relates to the control of elec? tric hoisting machinery for elevators and similar apparatus.

The general object of the invention is to provide a control whereby, when the o erator has started the elevator in the desire direction of travel, the starting switch may` be returned to its oli' or neutral position, and the elevator will continue in thatv direction of movement, until stopped automatically at the terminal, without further attention from the operator. v

further object of the invention is to provide means, independentv of vthe .startin limeans, whereby during the automatic trave oi the elevator, the operator can stop it at any selected intermediate landing. The running of the elevator therefore requiresno attention, after it is once started, unless it is desired to stop at an intermediate floor, and the operator is thus lett 'free toguard the passengers and watch his signals.

in the drawings, Figure. l is an across-theline diagram of the wiring for a push-button control eievator showing wirings and connections for a three-phase single speed motor without acceleration, each intermediate door being provided with two door-control switches one for the up-circuit and one for the down-circuit, all such switches being located in the operating circuits; Fig.Y 2 is a similar diagram et the loperating circuit, showing a single rioor control switch for each intermediate floor; Fig. 3 is a similar diagram ci the operating circuit, the iloor control switches for the intermediate loors being located in the holding circuit; Fig. l is a similar diagram or both power and operating circuits, the operating circuit diiering from the one shown in Fig. 3 in that the switch that initiates stoppin is magnetically lopened through the pushing ot the sto ping button by the operator; Figg is simi ar to Fig. li, except that it shows a magnet-controlled stop- .ping switch for each intermediatev iloor instead ot a single magnet-controlled stopping I switch lier all intermediate floors; Fi is an across-the-line diagram similar to el, except that a sliding contact switch is sucstituted for push-button control; Fig. 7 shows a modification of the sliding switch control shown inv Fig. 6, and Fig. 8 is a diagram of VYbothpower and operating circuits similar to those shown in Fig. 5, hut showing primary 5,5 windings for a two-speed motor andi also Application led July 31, 1926. Serial No. 126,197.

is illustrated in all but Figure 8 with a threephase single speed alternating current squirrel cage induction motor, without the usual acceleration. Anyone familiar with the art may add or use, when desired, any known method of acceleration or may substitute any other phase motor or a direct current motor in place of the alternating current motor, without departing :from the spirit of my invention.

The main elevator controller for the single speed alternating current motor is shown as composed of the two usual direction magnet switches. A main line or a potential magnet switch may be used, if desired, although not shown.

The power` circuits are shown in heavy lines and the switch-control circuits by light lines. In all the figures, A representsa power motor, B afmagnet switch coil for the up circuit, C a magnet switch coil for the down circuit, D an up directien starting switch, a down direction starting switch, F a stoning switch, G safety devices, ii-.l cams Jfor opening floor-stop switches, and d a hrahe me ffnet coii. The power supply lines ere d as L1, L2 and L3. @t3

. The switch Jtrames operated by coils l5 are mechanically interloched so when one of them is in operating position the other must be in inoperative position, thus insuring against short circuits.

rlhe safety devices G may he any ci 'the standard saieties required tor any particular installation, such as overtravel limits, safety or overspeed governor switch, door switches, emergency switch, etc.

The door controller may be a in the machine room designed (as shown in the drawings) with the cam element rl moving to the right when the elevator traveis up and to the left when the elevator travels down, and so arranged that it will open the contacts in a definite relation to the respective doors; or it may be'switches located in the hatchway, and opened by a` cam on the car;` or it may be a switch or switches on the car opened by cams at the floors.

A brake is provided, and ma he of any type that will he magnetically re eased by the energizing of coil J, and may be either spring or gravity set.

All@

` Y. Referring to Fig. 1, only the primary windings of the motor A are shown, the secondary windings being omitted. Power line'Ls is permanently connected b y conductor 1 to phase X of the motor windings, and lines L1 and L2 are connected respectively to phases Y and Z for driving the motor in the 11pdirection, and are reversely connected for driving it in the down-direction. lo4 For the 11p-direction, power line L1 is connected through lines 2 and 3 to phase Y of the motor windings, and power line L2 is connected through lines 4 and 5 to phase` Z of the motor windings. For the down direction, ower line L1 is connected through lines '6 an 5to phase Z of the motor windings and power line L2 is connected through lines 7 and 3 to phase Y of the motor windings.

The up direction control circuit comprises line 8, leading from line L1 to coil B, and

lines 9 and 10, leading from coil B to line vL2. The down direction control circuit com.

prises line 11 leading from line L1 to coil C,

and lines 12 and 10, leading from coil C to line L2.'

A normally open push button switch D isv interposed in line 8, and a by pass or shunt circuit 13 leads around switch l) through holding switch 14. In line 11 there is a similar push'buttonswitch E with a bypass or shunt circuit 15 and holding switch 16.

lncircuit 8, between switch D and coil B.

,there are intermediate floor switches 17 and .18 and a limit switch 19 for the top floor.- The construction shownis for a four story installation. lf there are `more or less doors, the only change necessa is in the number of switches for interme iate doors. Intermediate Hoor switches17 and 18 are closed except whenopened hy cam H, and there is a by pass or shunt line 20 leading around these intermediate switches.

In circuit 11` there is a limit switch 21 for the bottom floor and Hoor switches 22 and 23 for the, intermediate floors, and a by pass`- or shunt circuit 24 leading around intermediate switches 22 and 23.

A normally closed double pole push button switch F is interposed in circuits 20 and 24.

Safety devices G are interposed in line 10. common to both the up and down control circuits, and the coil J ot the brake is in a line 27 connecting lines 3 and 5,I so that the coil is energized whenever power is applied to the motor in either direction. v

Safety interlock normally closed `switches 28 and 29 are interposed in lines 9 and 12 respectively. A f

Normally open switches 30, 31, 32 and 33 are interposed in lines 2, 4, 6 and 7 respectively. V v

Means 34, actuated by the energization of coil B, operates to close normally open holding switch 14, open safety interlock switch 29, and close power switches^30 and 31. Similai-ly, means 35 actuated by coil operates to c I trol circuit, and holding switch 16 isclosed, Y

so that the car continues its downward movement after button E is released. Ifl the op erator does nothing further, the car continues to the bottom floor, where limit-switch 21 is opened, which results in deenergizing lcoil C' and allowing power switches 32 and 33 to vopen and stop the car.` At the same time, holding switch 16 is opened and safety switch 28 is closed. l.

If the operator desires to stop at the second floor, he pushes button F, opening shunt circuit 24, and, when cam H. opens,switch 22, coil C is deenergized, switches 16, 32 and 33 opened, switch 28 closed, and the ear stopped. lt will be noted that, when ,thus stopped at an intermediate floor, the ear may be started in either direction. Button F performs its function if pushed simultaneously with D or E, or at anytime thereafter before the desired floor is reached.

When it is desired to start the car in the up direction, either from the third Hoor position shown or from any lower Hoor, push button D is closed. This energizes coil B, closing switches 14, 30 and 31 and openingl switch 29, thus starting the car, insuring the continuance' of the motion after the push button is released, and preventing the closing of the down circuit before the opening of the up circuit.` ln the absence of further action on the part of the operator,I the car continues its upward movement until it reaches the top floor, when limit switch 19 is opened, coil B is de-energiz'ed, the car is stopped, and the control switches are returned to starting position.

If the car is started from a Hoor lower than the next to the top, it may be stopped at any intermediate floor by openin circuit 20 by means of ush button F and olding it open until'the intermediate floor switch is opened by cam H, whereupon coil B is 'de-energized-y and the car stopped.

Y It Will'be readily seen that coil J isenergized'whenever current is supplied to the motor in either direction, thus releasing the brake vwhen power is applied, and that the coil is. de-energized and the brake applied whenever power is shut ol from the motor.

YAlso since safety vdevices G are in a line com- Y mon to both the up and down control circuits,

they operate to stop the car in either direction of travel. The arrangement shown in Fig. 2 is similar to that shown in Fig. l, and corresponding parts are designated by the same refe-'rence characters, exce t the inodilied line in which safety devices are placed.

ln Fig. 2, the intermediate floor switches are omitted from lines 8 and 1l, and instead switches 36 and 37, for the 2nd and 3rd floors respectively, are interposed inline corresponding to line 10 in Fig. l, and common to both the up and down control circuits. A by pass or shunt circuit 38 connects line 10l on opposite sides of switches 36 and 37, and has switch F interposed therein.

The installation shown in Fig. 2 operates in exactly the same way as that shown in Fig. 1, except that, by the interposition of the intermediate floor switches in a line common to both the up and down control circuitsone switch for each floor and a single pole switch Fare suiiicient to control the car at the intermediate floors in either direction. It will be obvious that the same result may be obtained by interposing this intermediate ioor switch arrangement in any line common to the two control circuits.

The installation shown in Fig. 3 is similar to that shown in Figs. 1 and 2, and the same reference characters are used to designate the diierent parts except those which are modiiie lin Fig. 3, as well as in Fig. 2, the intermediate floor switches are omitted'from lines S and 1l. ln Fig. 3 the intermediate iioor switches are placed in holding lin-es i3a andi a, corresponding to lines 13 and l5 in Fig. 1.

in line 13a there are second r'loor switch 39 and 3rd floor switch 40, by passed by a line 41, while in line 15a there are similar tioor switches 42 and 43 by passed by line 44. A double push button switch F controls lines 4i and 44. The operation oi this installation is identical with thatl shown in Fig. 1, the only dierence being in the location oi the switches Fig. 4 is similar to Figs. 1 and 3 as `to most. features, and the saine reference numerals are used except'as to the modified part ot' the arrangement. In Fig. 4, lines 13b and 15b are constructed similarly to lines 13 and l5 in Fig. 3, exceptl that holding lines 4l and 44', with holdingswitches 45 and 46, respectively, are substituted for by pass lines 4l and 44.

A line 47 is provided connecting power lines 6 and 7 between their respective switches and the motor. This line-has a portion divided into parallel vlines, 43V and 49. Floor control switch is placed in branch 48. Line 47 passes through 'a coil F C that. when energized, actuates mechanism 5() which closes a holding switch 51 in branch 49 and opens switches and 46 in lines 41a and 44a.

In this construction, line 278L of brake coil J is shown attached to lines 6 and 7 instead of to lines 3 and 5. It will be understood that it isimmaterial at what points either brake circuit 27 or line 47 is attached to the two portions of the power circuits connected to phases Y :ind Z respectively and between the motor and the power switches.

The operation of the installation shown in Fig. 4 is similar to that described in connection with Fig. 1, except for the method of stopping at intermediate floors. When switch F in line 48 is closed, coil F C is energized and switch 51 is closed and holds the circuit through coil F C until power is switched oi of the motor. As long as coil F C is energized, switches 45 and 46 remain open. It follows that. when button F has been pushed, it may be immediately released and the by pass circuits 41 and 44l will remain open, so that the first opening of a floor switch by cam H cuts out the current from control coil B or C, as the case may be, and stops the can When power is cut olf from the motor. coil F C is dci-energized, switch 51 is allowed to open and switches 45 and 46 are allowed to close. Thereafter the car may he operated in either direction past intermediate iioors until huttonV F is pushed once more.

It will be. seen that, in this installation. the only attention required of the operator is to push the starting button and thereafter. if a stop is to be made at an intermediate door. push button F after passing the adiacent door. so that the operator has both hands free at the time the car stops.

The installation shown in Fig. 5 is similar to that shown in Fig. 4. and the same reierence characters are used ior all except the modiiied parte.

. The control circuits S and 1l and their con neetions are the saine in Fig. 5 as in Fia. except as to the by pass lines around the 'licor switches. In Fig. y5., there are separate by pass lines 41 and 41 around switches 39 and 40 respectively. and separate hv pass lines 44b and 44 around switches 42 and 43 respectivelv. Normally closed switches 52. 53, 54 and 55 are interposed in the lines hy passing switches 39. 40, 4Q and 43 respectively.

Control line 47I is shown connected to power lines 6 and 7. as in Fig. 4. it is separated for a distance into parallel lines 56 and 57. One end ci line 56 passes through coil F C2. while the other end is separated into parallel lines 58 and 59. A normally7 open push button switch F2 controls line 58, while a normally open holding switch 60 is inter- I posed in line 59. u Similarly. line 57 passes through a coil F C8, and is separated into lines 6l and- 62, which are in parallel. A push button switch FS controls line 61 and a holding switch- 63 is interposed in line 62.

The operation of the installation shown 1n Fig. 5 is the same as that shown 1n the preiao viouisly described figures except for stopping iat intermediate loors. When the car is in motion and the operator wishes to make a stop A at'the second iloor, for example, the

switches having been previously set for some other floor, he pushes in button F2, energizing coil FC. This coil actuates means 64 .which operates to close holding switch 60 and holding switch 60 maintains the circuit until the required operation has been performed.

211 Furthermore,I it will be noted that, if button F2 is pushed immediately after the car is started down, the car will continue past Hoor' three to floor two, as switches 53 and 55 in by pass lines 41 and 44 about the third floor control switches and 43, remain closed, not being affected by push button F2.

Similarly, if button Fs is pushed with the car in motion towards the third ioor, coil F C3 1s energized, and through means 65 closes holding switch 63 and opens by-pass switches 53 and 55, whereby the push button may be released immediately, and the car will be stopped when switch 40 or 43, as the case may be. is opened by the floor control cam H.

This installation is slightly more complicated than that shown in Fig. 4, but has thev advantage that pushing the appropriate button selects the desired floor for the next stop, at any time after the car has started, regardless of whether vor not there is an intervening floor, whereas the installation shown in Fig. 4 requires that the operator shall push 5 the button after all intervening oors have been passed. as the stop is made at the next floor after the button is pushed.'

The installation shown in Fig. 6 is similar i in eect to that shown in Fig. 4. and the correspending parts are designated bv the same characters. Fig. 6 differs fromA Fig. 4 chiefly b v lshowing a sliding or rotary type of switch in place of push buttons, and by showlng the intermediate floor control circuit in parallel with the other control circuits instead ofdi'rectly connected te the power circuit.

Slldmg or rotary bar K is adapted to make connection between power line L1 and contact l)7 at the end of line 8, contact E7 at the end of line 11, or contact F"l or F", described later. The floor control coil F C isj in `control line 66 connected at'one end toline 10 and 1 having its other end separated into branches 67 and 68 connected to terminals Fa and Fb respectively. A normally open holding switch 69 is interposed in branch 67 and is operativelyv connected to means 35 so that it is closed when coil C is energized. SA similar holding switch 70 in branch 68 holds a similar relation to coil B.

vA normally open holding switch 71 is closed by the energizing of coil F C, which also opens switches 45 and 46, as in Fig. 4. Aline l open, no current passes until the bar makes contactiwith terminal D", whereupon current passes through coil B, starting'the car andl closing switches 14 and70. After this, bar K may be moved back to neutral position and` the car will run until stopped by the terminal switch, unless the operator interyenes.

If the operator desires to stop'the car at an intermediate floor. he moves the bar down to contact terminal Fb. As switch 7 0' is held F C, closing holdingswitch 71 and opening by pass switches 45 and 46. Thereafter bar K may be moved back to neutral position andy current will pass through switch '71. line 73 in the drawing.

closed by coil B. this contact energizes coil Downward movement is 'eiected in like manner by moving bar K downward to make connection with contact E7, and then stoppage at an intermediate floor can be eected by moving bar K upward to make connection with contact F, the detailed operation being obvious romthe above description of the up direction operation.

v The installation shown in Fig. 7 operates in substantially the same way as that shown in Fig. 6. and the same reference characters are used for the same parts. The difference between the two installations is in the arrangement for stopping at intermediate doors. v p l ln the installation 'shown in Fig. 7. holding switch 71a, operated bv coil F C and corre'- 'sponding to switch I71 in Fig. 6. is interposed in a line 74a connecting line 67, between contact Fa and switch 69, with .power line L1. Lines 67 and 68 are connected, adjacent contacts Fa and Fb, by a line 75.

n operation, after the car'has started, bar K may be moved to contact` Fa or Fb. Because'of connection 7 5. a circuit will be completed through whichever of switches 69 and 70 is closed and through coil F C, which closes holding switch 71a and opens switches 45 and 46, so that the car is stopped at the next floor when cam H opens the respective Hoor switch. It will be seen that theloperatin is the same as with the installation shown in Fig. 6, except thatl stoppage maybe made at any floor in either direction by moving similar to that shown in Fig. 5 with the addition of provisions'for multi-speed operation.

In the construction shown in Fig. 8, there is a low speed motor A1 `and a high speed motor A2. These motorsy are three Vphase motors similar to that indicated in the other figures, except that they are shown with starting resistance. lIn the installation shown, the resistance coils R1, R2, R3, R, Rs and R2 are introduced in the Y of motor A1, and similarlyy resistances R", R2, R2, R1', R11 and R12 are introduced in the Y of motor A2. Switches 76, 77, 78 and 79 are arranged to cut out the resistance' in motor A1 and switches 80, 81, 82 and 83 are arranged to cut out the resistances in motor A2. v

The motors are energized by an arrangement of'lines similar to that shown in lthe other figures. The lines 2, 4, 6 and 7 with their switches 30, 31, 32 and 33 are identical with those shown in the other figures, and are given the same reference numerals. Line 32 is similar to line 3 in the otlier`iigures,`except that it -is connected to the phase Y1 of motor A1 and the phase Y2 of motor A2, instead of being connected to but one motor. Line 51, corresponding to line 5 in the other ligure, is connectedto phases Z1 of motor A1 and Z2 of motor A2 in a manner which will be described later.

Connected to phases Y1 and Z1 of motor A1 there is a line including a coil M which conl trols the resistance. Means 84 which is operated when coilM is energized, operates to first close switches 76 and 77, thereby cutting out resistances R1, R2 and R2. Thereafter in control timed sequence connected means 84:'A closes switches 78 and 79, thereby cutting out Vresistances R", R5 and' R1.

In a similar manner a coil N is ener izedl by a connection between phases Y2 and 2 of motor A2. Means 85 operated by the ener gizing of coil N first closes switches 80 and 81 to cut outv resistances R2,.R2, and R", and then b connected means 85l1 closes switches 82 an 83 to cut out vresistances R1", R11 and R12.

. Phase X1 of motor A1 is connected to power line L3 by a line 86. A line 87 similarly connects power line L8 to phase X2 of motor A2.

5 and is desi ence characters, with the addition of means,l

A line 88 connects phase Z1-of motor A1 to line 5, and line 89 connects hase Z2 of motor A2 to line 5*. Normally c osed switches 90 and 92 are interposed in lines 86 and 88 respectively, and normallyopened switches 91 and 93 areinterposed in lines 87 and 89 respectively. .The Vmeans for controlling the up and down circuits, and for controlling the various floor switches is the same as shown in ated b v the same referfor automatically regulating the connections to the two motors.

A line 94 isprovided connectin power line L1 to line 10 through a coil L Coil LC actuates means 95 which operates to open switches 90 and 92 and to close switches91 and 93.

A line 96 connects power line L1 to line 94 between line L1 and coil LC. A switch 97 is interposed in line 94, and is normally opened f.

until closed by the energizing of coil B. A similar switch 98 is interposed in line 96 and is normally open until closed by the energizing of coil C. In the construction shown,

, and 96.

An intermediate iioor switch control system and terminal switches, similar to those connected with lines 8 and 11, are connected to lines 94 and 96 respectively, and are designated by the same reference numerals with the addition of the letter Z.

The installation shown in Fig. 8 is operable in the following manner, which will be seen to be substantially the same as the operation of t-he installation shown in Fig. 5, withthe addition of the resistance and mult-i-speed features.

When the car is to be started in the up direction, push button Ds is actuated to close lines 8 and 94. This energizes coil B at once, closing switches 30 and 31 and energizing motor When motor A1 is energized, coil M is ener ized, and through suitabl timed mechanism cuts out the resistance. he timing of this mechanism may be controlled by dash pots or any other well known timing dev1ces.

' The ener 'zing of coil B also closes switch 97. A suita le timing mechanism may be inserted, so that the closing of switch 97 will follow the energizing ofcoil B after the sellected interval. When switch 97 is closed,

' the energizingvof-the highk speed motor. It

will be understood that energizing coil L C closes the holding switch 141, corresponding'- to the vholding switch 1li in connection with Y R9, R1, R11 and R11 are cut out. in properly timed sequence, as will be readily understood. It follows that the car is started upwardwith properly graduated acceleration by' the' mere push of button D8.

The timing y means in connection with switch 97, mentioned above, may be omitted,v it' desired, and current passed through coil LC practically simultaneously with the ener gizing of coil B, so that low speed motor A1 is cut out atonce and the car is started directly by the high speed motor.

The stopping of the car eitherv bythe terminal switches or at an intermediate fioor is eHected in the same way as described in connection with the'installation shown. in Fig. 5.

It has been explained how, after the car has started up or down, the operator may cause to stop automatically at any: pre-selecte 'i loor, merely by pushing the corresponding button F2 or F3, as the case maybe. After the selection has thus been made of the floor at which the car will make the `next stop, the operator may without stopping, change the selection merely by pushing the proper button. so as tostop at an intermediate floor. For example, upon starting downwardly from the top. floor, the button F2 may be pushed to set thefselecting device so that the car will automaticallystop at the second lloor. After this selection `has been made and while the car is under way, the selecting device may be changed, merely by pushing the button F s, so that the car will stop at the third ioor..

Suppose, however, that it is desired to change the selection to a floor beyond the one originally selected. For example, after starting downwardly from the top oor, the opera- 4 tor has pushed the button F8 to stop the car at the third licor and then finds that he does not wish to stop until he reaches the second oor. ln' order to change the selection in this manner, the coil FC3 must be de-energizedfto permit the switches 53, 531, and 551 tov open. For this purpose, a push button switch P-may be placed'in the line 47h, as shown in Figure .8.. Assoon as the button P is pushed to open the circuit through iine 47", the selecting mechanism is reset. rlhe button P may then be released and button F2 may then be .pushed to set the selecting mechanism to stop the car at the second floor. p

The door switches, terminal switches and by passes in lines 13b and 151 are duplicated in lines 'i3b1 and 15b. The by pass switches `in lines 41111, el, 44M and 44 are controlled by the same magnetic means, ,64 and 65, as controls the corresponding switches in circuits 4l etc. However, the Hoor switches in circuits 13b1 and l5bl are opened slightly before those in circuits-13b and 15", either b locating the switches differently or by provi ing separate cams H1. The result is that, as a floor is approached at which a stop is to be made, cam H1 opens the circuit through coil L C first, whereupon switches 91 and 93 are allowed to open, cle-energizing the high speed motor, and switches 90 and 92 are allowed to close, energizing the low speed motor. This eiiects the desirable gradualand accurate stopping of the car.

It will be readily understood that further connections may be provided, if desired, to

further control the gradual stopping, as well readily understand that polyphase magnets may be used instead of the single phase magnets, With obvious modifications in the installation.'

lVhile I have shown several definite diagrams of connections embodying my invention, it will be understood thatlI have not attempted to show all possible `embodiments of the invention, andv that other obvious ar-r rangements of the controlling devices, within the scope of the appended claims, are co1nprehended within the scope of my invention.

What I claim is:

1. An elevator installation comprising a car, an electric motor, a control system for the motor including a starting switch, means actuated by the starting operation of the switch to continue the energizing of the Inotor, after the switch has been returned to neutral position, until the car has reached a pre-selected door, Aand means independent of the starting switch and operable at any time, at the will of the operator, to cut out the floor first selected and to select another iioor, without stopping the motor.

2. ln `an elevator installation comprising an electric motor, electro-magnetic means for controlling the current to the motor, a starting switch for energizing said means, a holding switch actuated by said means for maintaining current through said means independ- `ently of the starting switch, an automatically ing switch for energizing said means, a holding switch actuated by said means for maintaining current through said means inde endently ofthe startin switch, an automatically operated floor switc for interrupting the current from said means at each floor, a byass for a ioor switch, a normally closed switch in the by-pass, electro-magnetic means for operated loor switch for interrupting the current from said means at cach floor, a bypass for a ioor switch, a normally closed switch in the by-pass, 4electro-magnetic means for opening the by-pass switch, a switch under control of the operator for energizing the last said electro-magnetic means, a by-pass around the last said switch, a normally open holding switch in said by-pass, and connections whereby the energizing ot the' last said magnetic means closes the last said holding switch.

5. In an elevator installation comprising an electric motor, electro-magnetic means for controlling the current to the motor, a starting switch for'energizing said means, aholding switch actuated by said 'meansfor maintaining current through said means inde endently of the starting switch, an automatically operated `floor switch for interrupting the current from said means at each licor, a bypass for a licor switch, a normally closed switch in the by-pass, electro-magnetic means for opening the by-pass switch, a switch under' control of the operator for energizing the last said electro-magnetic means, a by-pass around the last said switch, a lnormally open holding switch inlsaid by-pass, and connections whereby the energizingof the last said magnetic means closes the last said holding switch, the circuit of the last said electromagnetic means being connected to the circuit through the motor so that stopping of the motor releases said magnetic means.

6. In an elevator installation comprising an electric motor, an electro-magnetic means for controlling the current through the m0- tor, a circuit independent of the motor circuit 4for energizing the electro-magnetic means, a starting switch in the circuit of the electro-magnetic means, a by-pass around the starting switch, a normally open holding switch in the by-pass, connections whereby energizing of the electro-magnetic means closes the'holding switch, floor switches for each intermediate floor interposed in the circuit of the electro-magnetic means, said tloor `switches being normally closed, automatic means for o ening each of said switches when the car reac es the vrespective oor, a by-pass around the floor switch, a normally closed switch in the by-pass, and means under -control of the operator for opening the last said switch.

7. In'an elevator installation comprising an electric motor, an electro-magnetic means for controlling the current through the motor, a circuit independent of the motor circuit for energizin the electro-magnetic means, a starting switch inthe circuit of the electromagnetic means, a b -pass around the starting switch, a norma ly open holding switch in the by-pass, connections whereby energizing of the electro-magnetic means closes the holding switch, floor switches for v,

each intermediate floor interposed in the circuit of the electro-magnetic means, said floor switches .being normally closed, automatic means for opening eacli of said switches when the car reaches the respective oor, a. by-pass around the loor switch, a normally closed switch inthe by-pass, and means under control of the operator for opening the last said electro-magnetic means for opening the switch, a circuit connected to the power circuit of the motor for energizing the last said electro-ma netic means a' normally open switch in t e last said circuit closable at the will of theo erator, a byass around the last said switch, and a norma ly open holding switch in the byass closable upon the energizing of the means.

8. An installation 4in accordance with claim 7, and having a separate by-pass around the oor switch of 'each intermediate ooi, and se arate means for controlling the several switc es in these several by-passes.

9. An elevator installation comprising a plurality of motor windings of different speed, means operable to automatically control successive operation of the motor windings for stopping the car, means normally by-passing said controlling means, a starting switch, and a switch in the car independent of the starting switch for opening said by-passing means.

10. Iii an elevatorv installation comprising a plurality of motors, a control circuit for each motor, a normally closed switch in each circuit, automatic means for opening said switches in succession as the car approaches a predetermined point in its travel, a by-pass aroundeach of said switches, a normally closed switch in each by-pass, and common means within the control of the operator for openin corresponding by-pass switches in each o said circuits.

11. An elevator installation comprising a motor, a control circuit for the motor including a starting switchand a normally closed `switch, the last said means comprising ast said electro-magnetic y automatically operable stopping switch, a by-pass around said starting switch, a ma@- netic coil common to the main control circuit and the circuit through said by-pass, a.v switch in said lay-pass and held closed by said coil when the latter is energized, but adapt-Y ed to open when the coil is cle-energized, a by-pass around said stopping switch, and a switch in the last mentioned by-pass, which is normally .closed so as to render the automatically operable switch ineiectiveto stop the motor, but adapted to be manually opened to renderjthe same effective.

12. An elevator installation co'mprising a, motor, a control circuit therefor including a starting switch and a normally closed auto-4 matically operable stopping. switch for opening the circuit through the motor at a prede. termined point in its operation, a by-pass around said stopping switch, a magnetic coil common to the main control circuit and the circuit through said by-pass, a switch in said by-pass which is normally closed so that the stopping switch is ineffective to stop the luo- 13. An elevator installation comprising a motor, startinfy switch and a normally closedautomatically operable stopping switch for. opening the circuit through the motor at a preselected point in its operation, -a by-pass around said stopping switch, a switch in said by-pass, a magnetic coil for controlling the by-pass switch which is held open when said coil is energized, thereby rendering said au.

a control circuit. therefor including a a tomatically operable stopping switch eiectivev to stop the motor after the switch in the by-pass has been opened, and manually controlled moans for interrupting the circuit through said coil, thereby" permltting the bypass switch to close and rendering the stopping switch ineffective.

In testimony whereof I have hereunto signed my name to this specification.

ERNEST B. THURSToNr K i CERTHFHCAE @E CORRECTH,

Patent Ne. 1,714,285.

emma may 2i. me, te' I raum e. Tarascon.

lt te hereby certified that error appears in the printed specification et. the above numbered patent requiring correction as toiiowe: .Page 89 lane ZZ ciaam i2, ier the word "incttectiu/e"v read "eitective"; and that the aand Letters Pateat should he remi with this correction therein that the came may contorni te the record at the case in the Patent (ittica.

Signed and eeeied this 30th dey ot italy, A, D, @29

(Seal) ti., il. Etmres, Actie?, Ccrtaimtener'l et Patente,

CERTIFICATE OF CORRECTION.

Patent No. 1,714,285. Granted May 21, 1929, to

ERNEST B. THURSTON.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 8, line 27, claim 12, for the word "ineffective" read "effective"; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office. g

Signed and sealed this 30th day of July, A. D. 1929.

M. J. Moore, (Seal) Acting Commissioner of Patents. 

